<template>
  <div>
    <div class="dabox">
        <p>请选择你要购买的书籍</p>
    <ul>
      <li v-for="item, ind in arr" :key="ind">
        <span>{{ item ['name']}}</span>
        <button @click="buy(ind)">买书</button>
      </li>
    </ul>
    <table border="1" width="500" cellspacing="0">
      <tr>
        <th>序号</th>
        <th>书名</th>
        <th>单价</th>
        <th>数量</th>
        <th>合计</th>
      </tr>
      <tr v-for="item,index in arr" :key="index">
        <td>{{ index + 1 }}</td>
        <td>{{ item.name }}</td>
        <td>{{ item.price }}</td>
        <td>{{ item.count }}</td>
        <td>{{ item.price * item.count }}</td>
      </tr>
    </table>
    <p>总价格为: {{ allPrice }} </p>
    </div>
  </div>
</template>

<script>
export default {
  data () {
    return {
      arr: [
        {
          name: '水浒传',
          price: 107,
          count: 0
        },
        {
          name: '西游记',
          price: 192,
          count: 0
        },
        {
          name: '三国演义',
          price: 219,
          count: 0
        },
        {
          name: '红楼梦',
          price: 178,
          count: 0
        }
      ]
    }
  },
  methods: {
    buy (index) {
      this.arr[index].count++
    }
  },
  computed: {
    allPrice () {
      return this.arr.reduce((sum, obj) => {
        return (sum += obj.price * obj.count)
      }, 0)
    }
  }
}
</script>

<style scoped>
.nav_main {
  text-align: center;
 background-color: #d67d16;
}
th,td {
    border: 1px solid black !important;
  }

</style>
